Ruiz said he had some back pain last season, but not in the same area. Plus, he knows exactly when this most reason injury happened.

On April 19, the Phils second game in Milwaukee, an opposing hitter dribbled a slow roller in front of home plate. Ruiz fielded it and made an errant throw to Howard at first.

"That’s when I felt it," Ruiz said. "It was like a shot in my back. It was sore the next day and I told the trainers."

Ruiz said it was hard to sleep the first few nights after it happens, but he finally got a good night's sleep on Friday. In addition to maybe running the bases Sunday, he might throw to all the bases during BP.

"We’ll see [what happens] when I have to run the bases and do some more drills," he said.